The present invention relates to a method of treating a substrate with a zirconium alkoxide.
As used herein, xe2x80x9cautomotive refinishxe2x80x9d refers to compositions and processes used in the repair of a damaged automotive finish, usually an OEM provided finish. Refinish operations may involve the repair of one or more outer coating layers, the repair or replacement of entire automotive body components, or a combination of both. The terms xe2x80x9crefinish coatingxe2x80x9d or xe2x80x9crepair coatingxe2x80x9d may be used interchangeably.
Automotive refinishers must be prepared to paint a wide variety of materials. Examples of commonly encountered materials are one or more previously applied coatings, plastic substrates such as RIM, SMC and the like, and metal substrates such as aluminum, galvanized steel, and cold rolled steel. Bare metal and plastic substrates are often exposed as a result of the removal of the previously applied coating layers containing and/or surrounding the defect area. However, it is often difficult to obtain adequate adhesion of refinish coatings applied directly to exposed bare substrates.
Among the many factors influencing the degree of refinish coating/substrate adhesion are the type of exposed substrate, the presence or absence of adhesion promoting pretreatments and/or primers, the size of the exposed area to be repaired, and whether previously applied xe2x80x9canchoringxe2x80x9d coating layers surround the exposed repair area.
For example, refinish adhesion is particularly challenging when the exposed substrate is a bare metal such as galvanized iron or steel, aluminum or cold rolled steel. It is especially hard to obtain adequate refinish adhesion to galvanized iron. xe2x80x9cGalvanized iron or steelxe2x80x9d as used herein refers to iron or steel coated with zinc. xe2x80x9cSteelxe2x80x9d as used herein refers to alloys of iron with carbon or metals such as manganese, nickel, copper, chromium, molybdenum, vanadium, tungsten and cobalt.
Refinish operations have traditionally used adhesion pretreatments to overcome the adhesion problems associated with the coating of bare metal substrates. Pretreatment as used herein may refer to either mechanical or chemical alterations of the bare metal substrate. Mechanical alterations used to obtain improved adhesion include sanding, scuffing, and the like. Chemical alterations include treatment of the substrate with compositions such as chromic acid conversion coatings, acid etch primers and the like.
It would be desirable to provide a method that can improve the adhesion of coatings to substrates.
The present invention relates to a method comprising: providing a composition comprising a zirconium alkoxide and an acid, wherein the composition is not provided in a coating composition; and applying the composition to a substrate.
As used throughout, ranges are used as a shorthand for describing each and every value that is within the range. Any value within the range can be selected as the terminus of the range.
The adhesion of a coating on a substrate can be increased by treating the substrate with a zirconium alkoxide. The zirconium alkoxide is provided in a composition along with an acid. The composition is applied to a substrate. While the composition can comprise additional materials, the composition is not provided in a coating composition. Once the composition is applied to a substrate, the substrate can be rinsed, or the substrate need not be rinsed.
Zirconium alkoxide is a zirconium atom with four alkoxy groups. The zirconium alkoxide can be represented by the following general structure. 
wherein, R1, R2, R3, R4 are each independently an alkoxy group. The alkoxy group can contain heteroatoms anywhere in the alkoxy. Examples of heteroatoms include, but are not limited to, nitrogen, oxygen, phosphorous, and sulfur. The alkoxy groups can be bridged to one another. In one embodiment, the zirconium alkoxide does not contain any other metals.
A preferred zirconium alkoxide has the following general structure: 
wherein R5, R6, and R7 are each independently an alkoxy group as defined above.
Preferred zirconium alkoxides are Zirconium IV 2,2(bis-2-propenolatomethyl) butanolato, tris neodecanolato-O; Zirconium IV 2,2(bis-2-propenolatomethyl) butanolato, tris (dodecyl)benzensulfonato-O; Zirconium IV 2,2(bis-2-propenolatomethyl) butanolato, tris (dioctyl)phosphato-O; Zirconium IV 2,2(bis-2-propenolatomethyl) butanolato, tris 2-methyl-2-propenoato-O; Zirconium IV 2,2(bis-2-propenolatomethyl) butanolato, tris (dioxtyl)pyrophosphato-O; Zirconium IV 2,2(bis-2-propenolatomethyl) butanolato, tris 2-propenoato-O; Zirconium IV 2,2(bis-2-propenolatomethyl) butanolato, tris (2-ethylenediamino) ethylato; Zirconium IV bis 2,2(bis-2-propenolatomethyl) butanolato, bis (para amino benzoato-O); Zirconium IV bis 2,2(bis-2-propenolatomethyl) butanolato, bis (3-mercapto) propionato-O; Zirconium IV 2,2(bis-2-propenolatomethyl) butanolato, tris (2-amino) phenylato; Zirconium IV 2,2-dimethyl 1,3 propanedilato, bis (dioctyl) pyrophosphato-O, (adduct) 2 moles N,N-dimethylamino-alkyl propenoamide; Zirconium IV (2-ethyl, 2-propenolatomethyl) 1,3-propanedilato, cyclo bis 2-dimethylamino pyrophosphato-O,O adduct with 2 moles of methansulfonic acid; Zirconium IV tetrakis 2,2(bis-2propenolatomethyl)butanolato, adduct with 2 moles of ditridecyl, hydrogen phosphite; Zirconium IV 2-ethyl, 2-propenolatomethyl 1,3-propanediolato, cyclo di 2,2-(bis 2-propenolatomethyl) butanolato pyrophosphato-O,O; and Zirconium IV bis 2-ethylhexanolato, cyclo (di 2-ethylhexyl) pyrophosphato. All of the preceding zirconium alkoxides are available from Kenrich Petrochemicals, Inc. of Bayonne, N.J., and are listed in KEN-REACT(copyright) Reference Manual (Bulletin KR). Preferred zirconium alkoxides are Zirconium IV 2,2(bis-2-propenolatomethyl) butanolato, tris 2-methyl-2-propenoato-O and Zirconium IV 2,2(bis-2-propenolatomethyl) butanolato, tris 2-propenoato-O.
The above listed zirconium alkoxides have the following structures: 
Zirconium IV 2,2(bis-2-propenolatomethyl)butanolato, tris 2-methyl-propenoato-O 
Zirconium IV 2,2(bis-2-propenolatomethyl)butanolato, tris 2propenoato-O 
Zirconium IV 2,2(bis-2-propenolatomethyl)butanolato, tris neodecanolato-O 
Zirconium IV bis 2,2(bis-2-propenolatomethyl)butanolato, bis(para amino benzoato-O) 
Zirconium IV bis 2,2(bis-2-propenolatomethyl)butanolato, bis(3mercapto) propionato-O 
Zirconium IV 2,2(bis-2-propenolatomethyl)butanolato, tris(dodecyl)benzensulfonato-O 
Zirconium IV 2,2(bis-2-propenolatomethyl)butanolato, tris (dioctyl)phosphato-O 
Zirconium IV 2,2(bis-2-propenolatomethyl)butanolato, tris (dioctyl)pyrophosphato-O 
Zirconium IV 2,2(bis-2-propenolatomethyl)butanolato, tris (2-ethylenediamino)ethylato 
Zirconium IV 2,2(bis-2-propenolatomethyl)butanolato, tris (2-amino)phenylato 
Zirconium IV 2-ethyl, 2-propenolatomethyl 1,3-propanedilato, cyclo di 2,2-(bis 2-propenolatomethyl) butanolato pyrophosphato-O,O 
Zirconium IV bis 2-ethylhexanolato, cyclo (di 2-ethylhexyl) pyrophosphato 
Zirconium IV (2-ethyl, 2-propenolatomethyl) 1,3-propanediolato, cyclo bis 2-dimethylamino pyrophosphato-O,O adduct with 2 moles of methanesulfonic acid 
Zirconium IV 2,2-dimethyl 1,3 propanediolato, bis (dioxtyl) pyrophosphato-O, (adduct) 2 moles N,N- dimethylamino-alkyl propenoamide 
Zirconium IV tetrakis 2,2(bis-2 propenolatomethyl) butanolato, adduct with 2 moles of ditridecyl, hydrogen phosphite
The zirconium alkoxide can be present in the composition in any amount. Preferably, the zirconium alkoxide is present in the composition in an amount from about 0.01% to about 5% by weight of the composition. More preferably the zirconium alkoxide is present in the composition in an amount from about 0.5% to about 2% by weight of the composition.
The acid can be any acid used for cleaning and/or etching a substrate. The term acid can also include esters of the acid. Examples of the acid include, but are not limited to, phosphoric acid and phosphoric acid esters. Preferably, the acid is provided as an aqueous composition.
In the aqueous composition, the acid is preferably present in the aqueous composition from about 5% to less than 100% by weight. Additionally, the acid can used as a neat composition when the acid is a liquid at temperatures for coating processes. The acid can be present in the composition in any amount. Preferably, the acid is present in the composition in an amount from about 0.1% to about 10.0% by weight of the composition. More preferably the acid is present in the composition in an amount from about 2.0% to about 5.0% by weight of the composition.
The composition of the present invention can further comprise any other materials that are used for cleaning and/or treating a substrate for coating. Examples of other materials include, but are not limited to, solvents, such as ketones, alcohols, polyols, esters, aromatic hydrocarbons, aliphatic hydrocarbons, and glycol ethers.
The composition can be applied by brushing, wiping, spraying, dipping, roller-coating, or flow-coating.
The substrate can be a metal. Metals include, but are not limited to, steel, galvanized steel, iron, galvanized iron, aluminum, aluminum alloy, zinc, zinc alloy plated steel, cold rolled steel, titanium, titanium alloy, cadmium, and magnesium.
The method of the present invention can be used to treat a substrate in order to increase the adhesion of a coating to the substrate. The method can be used in a refinish operation wherein a refinish coating is applied to bare substrate, an OEM operation wherein an original equipment manufacturer coating is applied to a bare substrate, or for any operation wherein a coating is applied to a bare substrate. The coating can be any coating composition that comprises a resin. Preferably, the coating composition will be a primer composition because primers are traditionally applied to a substrate before basecoats and topcoats are applied.
The term resin includes any type of resin, binder, or polymer that can be included in a coating composition. Examples of resin include, but are not limited to, polyesters, polyacrylates, polyurethanes, polyamides, polylactones, polycarbonates, polyolefins, alkyds, oil-modified alkyds, epoxy-unsaturated fatty acid ester resins, addition resins with pendent olefinic groups, condensation resins with pendent olefinic groups, lacquer resins, and cellulose esters. Preferably, the resin is a polyurethane.
The adhesion of a coating to the substrate that has been treated according to the present invention can be increased up to 80% or more over the same coating applied to the substrate without being treated according to the present invention as measured by Ford test FLTM B1 104-01. The test ranks adhesion loss on a scale from 0 (no adhesion loss) to 10 (100%) adhesion loss.